An interesting discussion

[GregB]

Some interesing background on warfarin and dental procedures.

http://www.abc.net.au/rn/science/ockham/

Greg

 

[Ross]

"To answer the question on clinical evidence, I conducted a comprehensive search of the medical and dental literature. I discovered that the first controlled trial of dental extraction in patients on Warfarin therapy was conducted in 1983. It showed that it was not necessary to cease Warfarin prophylaxis for patients whose INR was within the normal range The findings of that paper were largely ignored for the next 20 years. Other small studies in humans and rabbits followed and all confirmed that it was unnecessary, and in fact potentially dangerous, to stop Warfarin for primary care dental extraction.

In 2000 a Delaware dentist, Michael Wahl, performed a meta-analysis of published papers which added up the outcomes of 2,400 individual dental procedures in 950 patients. It showed the incidence of embolic complications when stopping Warfarin was 1% and this was three times more likely than complications from bleeding."

And look where we are today. It's still being largely ignored.

 

[DrAllan]

The whole question of bleeding and surgical procedures needs to be put into proper perspective. There are two aspects, first the amount of blood loss and its affect on the patient, and second the question of visibility of the surgical field in relation to the volume of blood. For instance, when operating in a large sterile cavity with procedures that technically themselves are associated with large blood loss, there is a device call a ?cell saver? that literally vacuums up the blood, filters it and returns it to the patient?s circulation via a vein. Many times to stop bleeding, whether with cautery of sutures, one needs a dry field to work in. Thus we often clamp bleeding vessels prior to tying them off, or suction blood away from an area to allow cautery. Fortunately there are other techniques for different types of situations, but uncontrolled bleeding is a problem for your surgeon. Just as bad is continual oozing, which IS MORE of a problem with anticoagulation. However, in some areas, such as operating on the eye, a single drop of blood makes it impossible for the surgeon to see the field she is working on. Let me try to give you an example. Take a credit card out of your wallet and read the numbers. Now, put it on a flat plate and just cover it with tomato juice. Can you read the number? You can easily wipe it dry, but if I continue to pour juice over it you will not get to read it well. This is the same problem in surgery. Continuous oozing or bleeding after surgery is more of a problem on anticoagulants.

Now, there are four types of doctors. Smart surgeons, dumb surgeon, smart medical doctors and dumb medical doctors. The smart ones know what it is that they are trying to accomplish, and what the volume and flow of blood is likely to be. The question of dentists revolves about the fact that working in a dark cavity of the mouth with things in the way of vision such as teeth and gums and jaw, the presence of extra blood does not help the procedure.

 

[Blanche]

A good discussion, indeed.

A good discussion, indeed.

The discussion presents the information, arguments, research and sources that we have been discussing and sharing on this form for years now. It is good to see it in print, and in one place. Actually, this forum has presented and discussed most of the research and information published on anticoagulation and dental work, and certainly enough for a meta-analysis of the topic. "Ya saw it here first!" Bottom line, if you go off of your anticoagulation for dental work, you are at risk for a stroke. (1 in 34, according to one of the articles.)

Kind regards,
Blanche
....also, it is good to see DrAlan back!

 

[Guest]

My argument is that the American Dental Association has a set of guidelines telling what procedures are safe at what INRs. It has been out since 1997. (I have permission to reprint it on my site as long as I do not charge for the information.) Supposedly these are experts in the field reviewing the literature and making recommendations based on estimates of bleeding during the procedure, oozing afterwards etc. As an example, a simple extraction is rated as safe at an INR up to 2.5. This is the lower end of most valve people's safe INR range. Yet we continually have people who are told that they have to hold their warfarin for a week before a tooth can be pulled. It's hard to believe that everyone is a difficult case.

I have written before that at one of our meetings on anticoagulation a physician executive of a hospital told of ordering a copy of the Chest guidelines on antithrombotic therapy for every physician on staff. The person taking the order commented that she had never sold a large order to a hospital before -- only to law firms.

I've been an expert witness in 7 legal actions that have been settled. (I even helped get a successful outcome for a dentist who had a woman have a stroke in his dental chair.) Never once has the opposition's expert witness had the slightest idea of what the Chest guidelines say. Doctors are accused of ordering unnecessary lab tests just to have their rears covered in case of a lawsuit. It would be a whole lot simpler and cheaper if they would spend 5 minutes to have at least a vague idea of what the guidelines say. Juries might understand the analogy of tomato juice on a credit card but when you say that the person did not follow the best information in the field it goes heavily against the defendant. When the attorneys have followed my advice that are 6 favorable and 0 unfavorable. When they have not followed my advice they are 0 favorable and 1 unfavorable.

 

[GregB]

Thanks for clarification

Thanks for clarification

Thankyou for the further clarification.

The take away for me in the light of the above discussion is that if I find myself in a situation in which tooth extraction, or colonoscopy or gastroscopy is prescribed as a treatment, and the practitioner suggests stopping of warfarin for any number of doses...then I seek another opinion.

My next question. Are there other relatively routine procedures, apart from the three mentioned above, for which a medical/dental practitioner may suggest withholding warfarin dosage?

I assume warfarin is stopped for most or all major surgical events and we take our chances?

Greg

 

[Guest]

You can use "bridge therapy" with a low-molecular wieght heparin. I'm not sure what the brand name is in the Land of Oz. Try google Australia and type in enoxaparin and dalteparin and see what you get.

As with any therapy it is not foolproof. This is the ranking of who does the best to who does the worst.

1. Warfarin stopped cold turkey and no complications develop
2. LMWH used after warfarin stopped and no complications develop
3. LMWH used after warfarin stopped and complications develop
4. Warfarin stopped cold turkey and complications develop

So LMWH sorta hedges the bets.